Here's why:
* Sediment Deposition: Rivers carry sediment (sand, silt, clay) as they flow. When a river reaches a larger body of water (like a lake or ocean), its velocity slows down. This causes the sediment to settle out and accumulate at the river's mouth.
* Triangular Shape: Over time, the accumulated sediment forms a fan-shaped or triangular landform. This is because the river typically splits into multiple channels (distributaries) as it enters the larger water body, spreading the sediment out.
* Named After the Greek Letter: The term "delta" comes from the Greek letter Δ (delta), which resembles the shape of the landform.
Some famous deltas around the world include the Nile Delta, the Mississippi Delta, and the Ganges Delta.
